Latch device and vehicle seat

ABSTRACT

A latch device includes a latch engageable with a rod portion of a striker, and is capable of transition to a locked state in which the latch is engaged with the rod portion and to an unlocked state in which the latch is disengaged from the rod portion, and includes a first shaft member that supports the latch in a manner that permits the latch to rotate, and a base member that supports the first shaft member. The base member is a unitary member which includes a first support wall disposed on one side of the latch and configured to support one end of the first shaft member, a second support wall disposed on an other side of the latch and configured to support an other end of the first shaft member, and a connecting wall that connects the first support wall and the second support wall.

TECHNICAL FIELD

The present invention relates to a latch device including a latchengageable with a rod portion and a vehicle seat including the latchdevice.

BACKGROUND ART

Conventionally, a latch device including a latch engageable with a rodportion of a striker or the like and capable of transition to a lockedstate in which the latch is engaged with the rod portion and to anunlocked state in which the latch is disengaged from the rod portion isknown in the art. For example, Patent Document 1 discloses a latchdevice comprising a latch, a latch shaft that supports the latch in amanner that permits the latch to rotate, and a base plate and a backplate that support the latch shaft. This latch device is assembled byarranging the latch between the base plate and the back plate and fixingboth ends of the base plate and the back plate to one another by a boltand a nut.

CITATION LIST Patent Literature

-   Patent Document 1: JP 2006-248330 A

SUMMARY OF INVENTION

By the way, for latch devices or vehicle seats such as car seatsincluding latch devices, reduction in the number of parts would bedesirable for downsizing, weight reduction, cost reduction and the like.

Thus, it is an object of the present invention to provide a latch deviceand a vehicle seat that can be made with a reduced number of parts.

It is a further object to minimize deformation of a base member.

It is a further object to reduce the size and/or weight of the latchdevice.

It is a further object to reduce the load on a latch.

It is a further object to easily manufacture the base member.

It is a further object to improve the rigidity of the base member.

It is a further object to minimize twisting of the latch.

A latch device which achieves the aforementioned object includes a latchengageable with a rod portion and is capable of transition to a lockedstate in which the latch is engaged with the rod portion and to anunlocked state in which the latch is disengaged from the rod portion,the latch device comprising: a shaft member that supports the latch in amanner that permits the latch to rotate; and a base member that supportsthe shaft member, wherein the base member is formed as a unitary memberwhich comprises a first support wall disposed on one side of the latchin a direction of a rotational axis of the latch and configured tosupport one end of the shaft member, a second support wall disposed onan other side of the latch in the direction of the rotational axis ofthe latch and configured to support an other end of the shaft member,and a connecting wall that connects the first support wall and thesecond support wall.

According to this configuration, the number of parts of the latch devicecan be reduced compared to the case where the latch is disposed betweena base plate and a back plate.

In the aforementioned latch device, the shaft member may be fixed to thebase member to restrict an increase in distance between the firstsupport wall and the second support wall.

According to this configuration, deformation of the base member in thedirection in which the distance between the first support wall and thesecond support wall would otherwise increase can be restricted. Further,the number of parts of the latch device can be reduced. Also, it ispossible to reduce the size and/or weight of the base member, and thusto reduce the size and/or weight of the latch device.

In the aforementioned latch device, the latch may comprise a latchcontact surface contactable with the rod portion in the locked state,and the base member may comprise a base contact surface disposed on asame side of the rod portion as a side on which the latch contactsurface is disposed, the base contact surface being configured to becontactable with the rod portion in the locked state, together with thelatch contact surface.

According to this, when the rod portion contacts the latch contactsurface, it also contacts the base contact surface, and thus the loadfrom the rod portion can be distributed between the latch and the basemember. Thereby, the load on the latch can be reduced.

In the aforementioned latch device, the base contact surface maycomprise a first contact surface formed on the first support wall, and asecond contact surface formed on the second support wall.

According to this, the load from the rod portion can be distributedbetween the first support wall and the second support wall of the basemember disposed on both sides of the latch. Thereby, the load on thelatch can be further reduced.

In the aforementioned latch device, the first support wall, the secondsupport wall and the connecting wall may form a U shape.

According to this, the base member including the first support wall, thesecond support wall and the connecting wall can easily be manufactured,for example, by bending a metal sheet.

In the aforementioned latch device, the first support wall may comprise:a first wall portion that supports the one end of the shaft member; asecond wall portion disposed in a position different from a position ofthe first wall portion in the direction of the rotational axis, anddisposed in a position different from a position of the first wallportion as viewed in the direction of the rotational axis; and a thirdwall portion that connects the first wall portion and the second wallportion.

According to this, since a stepped shape is formed on the first supportwall 11, the rigidity of the base member 10 can be enhanced.

In the aforementioned latch device, a section connecting the first wallportion and the third wall portion, and a section connecting the secondwall portion and the third wall portion may each include at least onearcuate portion as viewed in the direction of the rotational axis.

According to this, the rigidity of the base member can be furtherenhanced.

The aforementioned latch device may be configured to further comprise: aratchet rotatably supported on the base member and configured to engagethe latch to thereby maintain the locked state and the unlocked state; alever member rotatably supported on the latch and configured to transfermotion of the ratchet to the latch; and a biasing member engaged withthe ratchet and the lever member, wherein the lever member is formed asa unitary member which comprises a lever body, and a biasing memberattachment portion with which the biasing member is engaged, the biasingmember attachment portion extending from the lever body and bending to aside opposite to a side on which the latch is disposed in the directionof the rotational axis.

According to this, the number of parts of the latch device can bereduced.

The aforementioned latch device may be configured to comprise a loadbearing member that contacts the rod portion and receives a load fromthe rod portion, wherein the first support wall includes a first wallportion configured to support the one end of the shaft member, a secondwall portion disposed in a position different from a position of thefirst wall portion in the direction of the rotational axis, and disposedin a position different from a position of the first wall portion asviewed in the direction of the rotational axis, and a third wall portionthat connects the first wall portion and the second wall portion and hasan insert hole formed therein, and wherein the load bearing memberincludes a body portion that extends along the first wall portion towardthe third wall portion, a hook portion that is engaged with an end ofthe first wall portion disposed opposite to the third wall portion, afirst load bearing surface that is contactable with the rod portion andreceives a load from the rod portion which load is directed from the endportion of the first wall portion toward the third wall portion, and aninsert portion that projects from the body portion and is engaged withthe insert hole.

According to this, since the insert portion is engaged with the inserthole in the third wall portion, it is possible to restrain the loadbearing member from moving in the direction of the rotational axis whena load is applied from the rod portion to the first load bearingsurface. It is thus possible to stably receive the load from the rodportion by the base member via the load bearing member.

In the aforementioned latch device, the load bearing member may beconfigured to include a second load bearing surface contactable with theend of the first wall portion.

According to this, the load imposed on the load bearing member from therod portion can be stably received by the first wall portion (basemember) via the second load bearing surface.

In the aforementioned latch device, the load bearing member may beconfigured to include a third load bearing surface that is contactablewith the third wall portion.

According to this, the load imposed on the load bearing member from therod portion can be stably received by the third wall portion (basemember) via the third load bearing surface.

In the aforementioned latch device, the insert portion may be configuredto include a claw that is engaged with the third wall portion in such amanner that the third wall portion is sandwiched between the claw andthe body portion.

According to this, it is possible to restrain the load bearing memberfrom moving in the direction of thickness of the third wall portion.

The aforementioned latch device may be configured such that the firstwall portion includes an access groove in which the rod portion islocated in the locked state, and the hook portion is engaged with thedeepest portion of the access groove.

A vehicle seat which achieves the above object may be configured suchthat it comprises: a seat frame which forms a frame for a seat; and theaforementioned latch device fixed to the seat frame, wherein the seatframe comprises a frame contact surface disposed on a same side of therod portion as a side on which the latch contact surface and the basecontact surface are disposed, the frame contact surface beingcontactable with the rod portion in the locked state, together with thelatch contact surface and the base contact surface.

According to this, since the rod portion also contacts the frame contactsurface when it contacts the latch contact surface and the base contactsurface, the load from the rod portion can be distributed among thelatch, the base member, and the seat frame. Thereby, the load on thelatch can be further reduced.

A vehicle seat which achieves the above object may be configured suchthat it comprises: the aforementioned latch device; a seat frame whichforms a frame for a seat; a seatbelt anchor fixed to a side of the seatframe; and a fixing member configured to fix the latch device to theside of the seat frame, wherein the shaft member has a tubular shape,wherein the fixing member extends through an interior of thetubular-shaped shaft member and is fixed to the side of the seat frame,and wherein a location of a fixing point of the seat frame and theseatbelt anchor is different from a location of the fixing member asviewed in the direction of the rotational axis.

According to this, twisting of the latch can be minimized when the seatbelt anchor is pulled.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a vehicle seat including a latch deviceaccording to an embodiment.

FIG. 2 (a) is an exploded perspective view of the latch device, and (b)is a perspective view of a ratchet.

FIG. 3 is a diagram showing the latch device in a locked state.

FIG. 4 is a sectional view taken along X-X of FIG. 3 .

FIG. 5 is a side view of a base member with a load bearing memberattached thereto.

FIG. 6 is a side view of a rear end of a side frame, the latch device,and a seat belt anchor.

FIG. 7 is a diagram explaining the operation of the latch device.

FIG. 8 is a diagram explaining the operation of the latch device.

FIG. 9 is a diagram explaining the operation of the latch device.

FIG. 10 is a diagram showing the latch device in an unlocked state.

FIG. 11 (a) is a diagram showing the case where a large load is appliedto move the seat forward in the locked state, and (b) a sectional viewtaken along Y-Y of (a).

FIG. 12 is a side view of a rear end of a side frame, a latch device,and a seat belt anchor implemented as a first modification.

FIG. 13 (a) is a perspective view of a base member, and (b) is a sideview of a latch device according to a second modification.

FIG. 14 is an exploded perspective view of a latch device according to athird modification.

FIG. 15 is a sectional view of a load bearing member and a base memberin the third modification.

FIG. 16 is a side view of the load bearing member and the base member inthe third modification.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a description of an embodiment of the present inventionwill be given with reference to the accompanying drawings.

As shown in FIG. 1 , a vehicle seat of the present embodiment isconfigured as a car seat S installed on an automobile and mainlyincludes a seat cushion S1, a seat back S2, and a latch device 1. Theseat cushion S1 includes a seat frame F1 which constitutes a frame forthe seat cushion S1, and is formed by covering the seat frame F1 with apad material made of urethane foam or the like and a covering materialmade of fabrics, leather or the like.

The seat frame F1 comprises left and right side frames F11 (only one isshown) arranged laterally apart. In the present embodiment, the latchdevice 1 is fixed to the left side frame F11. The latch device 1includes a latch 20 and is configured to be capable of transition to alocked state in which the latch 20 is engaged with a rod portion P1 of astriker P provided on the car floor FL of a car and to an unlocked state(see FIG. 10 ) in which the latch 20 is disengaged from the rod portionP1. In the present embodiment, the front-rear, left-right and up-downdirections are defined with respect to an occupant of a car seat S,although it is needless to say that the latch device 1 may be used inany position.

As shown in FIG. 2(a), the latch device 1 mainly comprises a base member10, a latch 20, a first shaft member 30 as a shaft member, a ratchet 40,a second shaft member 50, a lever member 60, a tension spring 70 as abiasing member, and a load bearing member 80.

The base member 10 is a member that supports components such as thelatch 20 and the ratchet 40 and is made of sheet steel. Details of thebase member 10 will be described afterwards.

The latch 20 is a member engageable with the rod portion P1 of thestriker P (see FIG. 3 ) and includes a first opening 21, an engagementgroove 22, a lock recess 23 and an open abutment surface 24. The firstopening 21 is a through hole that passes through the latch 20 in theleft-right direction. The latch 20 has its first opening 21 fitted androtatably supported on the first shaft member 30, and thus is rotatablysupported on the base member 10 via the first shaft member 30. A tubularprojection 25 nearly in the shape of a hollow cylinder is formed on aside surface of the latch 20, the tubular projection 25 projecting fromthe periphery of the first opening 21 in a direction of a rotationalaxis of the latch 20 (hereinafter referred to as “the direction of therotational axis”) which corresponds to the left-right direction (seealso FIG. 4 ). On the upper side of the first opening 21 there is formeda pin hole 26 into which a pin 29 that rotatably supports the levermember 60 is press-fitted.

The engagement groove 22 is a groove that is engaged with the rodportion P1 of the striker P and opens toward the front. The latch 20 isconfigured such that a portion on the lower side of the engagementgroove 22 forms a hook portion 27, and a portion on the upper side ofthe engagement groove 22 facing the hook portion 27 forms a projectionportion 28. The lock recess 23 is a recess dented toward the firstopening 21 which is formed on the upper side of the engagement groove22. The open abutment surface 24 is a part of the outer periphery of thelatch 20 adjacent to the upper side of the lock recess 23, and iscontacted by the ratchet 40 in the unlocked state to maintain the latch20 in an unlocked state position. As shown in FIG. 3 , the open abutmentsurface 24 is a convex curved surface projecting outward on the latch 20and the direction toward the center of curvature of the open abutmentsurface 24 (refer to the arrow) is displaced to one side, specificallythe front side, of a rotational axis A1 of the latch 20, over the wholerange with which the ratchet 40 is abuttable.

The latch 20 has a latch contact surface 22A which is contactable withthe rod portion P1 of the striker P in the locked state. The latchcontact surface 22A is a bottom (rear) surface of the engagement groove22 and is disposed on the rear side of the rod portion P1 in the lockedstate.

Returning to FIG. 2(a), the latch 20 includes a latch body 20A formed bystamping sheet steel, and a plastic cover 20B formed by insert moldingso as to cover a part of the latch body 20A. The cover 20B covers theinner periphery of the first opening 21 and the inner surface of theengagement groove 22. The tubular projection 25 is formed of plastic aspart of the cover 20B. On the other hand, the inner surface of the lockrecess 23 and the open abutment surface 24 are not covered with thecover 20B and the metal latch body 20A is exposed. The tip of the hookportion 27 that catches the rod portion P1 is also not covered with thecover 20B and the latch body 20A is exposed.

The first shaft member 30 is a member that supports the latch 20 in amanner that permits the latch 20 to rotate and includes a first tubularportion 31 formed nearly in a shape of a hollow cylinder, and a firstflange portion 32 formed on one end of the first tubular portion 31.

The ratchet 40 is a member that is engaged with the latch 20 to maintainthe locked state and the unlocked state, and is made of sheet steel. Theratchet 40 includes a base portion 40A in which a second opening 41 isformed, and an action portion 40B nearly in the shape of a fan. Thesecond opening 41 is a hole which passes through the ratchet 40 in thedirection of the rotational axis. The ratchet 40 has its second opening41 fitted and rotatably supported on the second shaft member 50, andthus is rotatably supported on the base member 10 via the second shaftmember 50. The rotational axis A2 of the ratchet 40 is parallel with therotational axis A1 of the latch 20.

A rearside corner of the action portion 40B is configured as a lockengagement portion 42 that abuts the latch 20. The lock engagementportion 42, in the locked state, enters the lock recess 23 and functionsto maintain the latch 20 in a locked state position, and, in theunlocked state, abuts the open abutment surface 24 of the latch 20 andfunctions to maintain the latch 20 in an unlocked state position. Arivet hole 43 to which a rivet 49 is connected is formed in the frontend of the action portion 40B. A cable, rod or the like connected to anactuation member such as a lever (not shown) for actuating the latchdevice 1 is connected directly, or indirectly via another member, to therivet 49 fixed to the ratchet 40. The ratchet 40 is configured to rotateabout the rotational axis A2 through actuation of the actuation memberwhich causes the cable or the like to be pulled and causes the rivet 49to be pulled or pushed.

As shown in FIG. 2(b), the ratchet 40 includes a restriction portion 44formed on the base portion 40A, and a projection 45 formed on the actionportion 40B. The restriction portion 44 is a portion nearly in the shapeof a hollow cylinder, projecting to the right from the periphery of thesecond opening 41. The restriction portion 44 projects by a lengthcorresponding to a thickness of the lever member 60, and functions tolimit play of the lever member 60 in the locked state effected by thelever member 60 biased by a tension spring 70 abutting the outerperipheral surface of the restriction portion 44. The projection 45 is anearly cylindrical columnar portion projecting to the right from a sidesurface of the action portion 40B at a location frontward of the lockengagement portion 42.

As shown in FIG. 2(a), the second shaft member 50 is a member thatsupports the ratchet 40 in a manner that permits the ratchet 40 torotate and includes a second tubular portion 51 formed substantially asa hollow cylinder, and a second flange portion 52 formed on one end ofthe second tubular portion 51.

The lever member 60 is a member that transfers motion of the ratchet 40to the latch 20 and is made of sheet steel. The lever member 60 includesa lever body 60A, and a spring attachment portion 60B as a biasingmember attachment portion. The lever body 60A is elongated in thefront-rear direction and has a shaft hole 61, and a nearlydiamond-shaped guide hole 62. The shaft hole 61 is formed in the rearend portion of the lever body 60A. The lever member 60 is rotatablysupported on the latch 20 with the shaft hole 61 rotatably fitting on apin 29 fixed on the latch 20. The projection 45 formed on the ratchet 40is located in the guide hole 62. The frontward edge of the lever body60A forms a stopping surface 63 which abuts the restriction portion 44of the ratchet 40 and limits play of the lever member 60. The springattachment portion 60B extends from an upper end of the rear end portionof the lever body 60A and bends in a direction opposite to the side onwhich the latch 20 is disposed in the direction of the rotational axis,specifically, to the right. A spring engagement portion 64 with a shapedented toward the front is formed on the rear surface of the springattachment portion 60B. The lever body 60A and the spring attachmentportion 60B of the lever member 60 are integrally formed by stamping andbending sheet steel by presswork. That is, the lever member 60 is aunitary member including the lever body 60A and the spring attachmentportion 60B.

The tension spring 70 is a member that provides a biasing forceconstantly pulling the rivet 49 connected to the ratchet 40 and thespring attachment portion 60B of the lever member 60 toward each other,with one end engaging the ratchet 40 via the rivet 49 and the other endengaging the spring engagement portion 64 formed on the springattachment portion 60B of the lever member 60. The biasing force of thetension spring 70 also acts as a force that presses the lock engagementportion 42 of the ratchet 40 against the outer periphery of the latch20.

The base member 10 rotatably supports the latch 20 by supporting thefirst shaft member 30, and rotatably supports the ratchet 40 bysupporting the second shaft member 50. The base member 10 includes afirst support wall 11, a second support wall 12, and a connecting wall13.

The first support wall 11 is a wall that supports one end of the firstshaft member 30 and one end of the second shaft member 50, and thesecond support wall 12 is a wall that supports the other end of thefirst shaft member 30. As shown in FIG. 4 , the first support wall 11 isdisposed on one side of the latch 20 in the direction of the rotationalaxis, and the second support wall 12 is disposed on the other side ofthe latch 20 in the direction of the rotational axis. Specifically, thefirst support wall 11 is disposed on the right side of the latch 20 andthe second support wall 12 is disposed on the left side of the latch 20.Accordingly, the first support wall 11 and the second support wall 12are disposed so as to sandwich the latch 20 in the direction of therotational axis. Returning to FIG. 2(a), the first support wall 11 iselongated in the front-rear direction, and the second support wall 12 isformed so as to face the rear end of the first support wall 11 in thedirection of the rotational axis.

The connecting wall 13 is a wall connecting the first support wall 11and the second support wall 12 and is disposed so as to face the latch20 in a direction orthogonal to the direction of the rotational axis. Inthe present embodiment, the connecting wall 13 is disposed on the rearside of the latch 20. The connecting wall 13 extends in the direction ofthe rotational axis and connects the rear ends of the first support wall11 and the second support wall 12. The first support wall 11, the secondsupport wall 12 and the connecting wall 13 form a U shape as viewed inthe up-down direction. The base member 10 is formed by bending sheetsteel by presswork and is integrally formed of the first support wall11, the second support wall 12 and the connecting wall 13. That is, thebase member 10 is a unitary member including the first support wall 11,the second support wall 12 and the connecting wall 13.

The first support wall 11 includes a first wall portion 11A, a secondwall portion 11B, and a third wall portion 11C. The first wall portion11A is a portion that supports one end of the first shaft member 30 andone end of the second shaft member 50. The base member 10 includes afirst latch support hole 14A formed in the second support wall 12, asecond latch support hole 14B formed in the first wall portion 11A ofthe first support wall 11, a ratchet support hole 15, and an accessgroove 16. The first latch support hole 14A and the second latch supporthole 14B are holes that are engaged with the first tubular portion 31 ofthe first shaft member 30, and the ratchet support hole 15 is a holethat is engaged with the second tubular portion 51 of the second shaftmember 50. The first latch support hole 14A, the second latch supporthole 14B, and the ratchet support hole 15 are through holes provided inthe direction of the rotational axis. The access groove 16 is a groovein which the rod portion P1 of the striker P is located in the lockedstate and is open toward the lower side.

The second latch support hole 14B is disposed farther rearward relativeto the access groove 16, and the ratchet support hole 15 is disposedfarther frontward relative to the access groove 16. In other words, theaccess groove 16 is positioned between the second latch support hole 14Band the ratchet support hole 15 with respect to the front-reardirection. The first latch support hole 14A is disposed so as to overlapthe second latch support hole 14B as viewed in the direction of therotational axis. In the present embodiment, the ratchet support hole 15is formed in a nearly circular reinforcing projection 11P that projectsfurther toward one side in the direction of the rotational axis than theportion of the first wall portion 11A in which the second latch supporthole 14B is formed, specifically, to the left side. That is, the firstwall portion 11A of the base member 10 is configured such that theportion (reinforcing projection 11P) on which the ratchet 40 is attachedvia the second shaft member 50 projects further to the left than theportion on which the latch 20 is attached via the first shaft member 30.

The second wall portion 11B of the first support wall 11 is disposed ina position different from a position of the first wall portion 11A inthe direction of the rotational axis. Specifically, the second wallportion 11B is disposed further to the right relative to the first wallportion 11A. Further, as shown in FIG. 5 , the second wall portion 11Bis disposed in a position different from a position of the first wallportion 11A as viewed in the direction of the rotational axis.Specifically, the second wall portion 11B is disposed higher than thefirst wall portion 11A. The second wall portion 11B includes a guiderecess 17 on an upper edge of a front end thereof. The guide recess 17is formed between two restriction projections 17A, 17B projectingupwards. The bottom surface of the guide recess 17 is formed nearly inthe shape of an arc of which the center of curvature coincides with therotational axis A2 of the ratchet 40 (see FIG. 3 ). The rivet 49connected to the ratchet 40 is positioned in the guide recess 17 (seeFIG. 3 ).

The third wall portion 11C is the portion connecting the first wallportion 11A and the second wall portion 11B. In more detail, the thirdwall portion 11C extends in the direction of the rotational axis andconnects the upper end of the first wall portion 11A and the lower endof the second wall portion 11B. The first support wall 11 includes afirst connecting section 11D that is a section connecting the first wallportion 11A and the third wall portion 11C, and a second connectingsection 11E that is a section connecting the second wall portion 11B andthe third wall portion 11C. The first connecting section 11D and thesecond connecting section 11E each have a shape including two nearlyarcuate portions. Specifically, the first connecting section 11D and thesecond connecting section 11E each have a shape in which a first arcuateportion R1 and a second arcuate portion R2 are aligned in the front-reardirection. The arcuate portions R1, R2 each have a shape with a nearlyconvex curved surface projecting upward.

As shown in FIG. 2(a) and FIG. 3 , the base member 10 further includes abase contact surface 18. The base contact surface 18 is a surfacecontactable with the rod portion P1 of the striker P in the lockedstate, together with the latch contact surface 22A of the latch 20. Inthe locked state, the base contact surface 18 is disposed on the rearside of the rod portion P1, on the same side as that on which the latchcontact surface 22A of the latch 20 is disposed. In the presentembodiment, the base contact surface 18 includes a first contact surface18A formed on the first support wall 11, and a second contact surface18B formed on the second support wall 12. Specifically, the firstcontact surface 18A is the rear surface of the access groove 16, and thesecond contact surface 18B is the front surface of the second supportwall 12. The first contact surface 18A and the second contact surface18B are disposed so as to overlap each other as viewed in the directionof the rotational axis.

As shown in FIG. 4 , the first shaft member 30 is fixed to the basemember 10 together with the latch 20 by arranging the first tubularportion 31 through the first latch support hole 14A of the secondsupport wall 12, the first opening 21 of the latch 20, and the secondlatch support hole 14B of the first support wall 11, and spreading andclinching the tip of the first tubular portion 31. The first shaftmember 30 fixed to the base member 10 includes a spread clinched portion33 on the tip of the first tubular portion 31. The first shaft member 30restrains the second support wall 12 from moving away from the firstsupport wall 11 by the first flange portion 32, and restrains the firstsupport wall 11 from moving away from the second support wall 12 by theclinched portion 33. In this way, the first shaft member 30 restrictsthe increase in distance between the first support wall 11 and thesecond support wall 12.

On the other hand, the second shaft member 50 shown in FIG. 2(a) isfixed to the reinforcing projection 11P of the base member 10 togetherwith the ratchet 40 by arranging the second tubular portion 51 throughthe second opening 41 of the ratchet 40 and the ratchet support hole 15of the first support wall 11, and spreading and clinching the tip of thesecond tubular portion 51.

The load bearing member 80 is a member that contacts the rod portion P1of the striker P and is subjected to a load from the striker P (rodportion P1), and is made of plastic. The load bearing member 80 has anearly U-shaped cross section which includes a first clamping portion 81and a second clamping portion 82 spaced apart in the direction of therotational axis, and a connecting portion 83 which connects the lowersections of the first clamping portion 81 and the second clampingportion 82. The distance between the first clamping portion 81 and thesecond clamping portion 82 is almost the same as the sheet thickness ofthe base member 10. The connecting portion 83 is formed so that theupper surface thereof is contoured to follow the shape of the bottom(upper) surface of the access groove 16. As shown in FIG. 5 , the loadbearing member 80 is attached to the base member 10 with the firstclamping portion 81 and the second clamping portion 82 sandwiching theportion of the support wall 11 on the upper side of the access groove 16and with the connecting portion 83 disposed on the bottom side of theaccess groove 16. The second clamping portion 82 is formed with anengagement lug 84 that is engaged with an engagement hole 19 formed inthe first wall portion 11A of the first support wall 11. The undersidesurface of the connecting portion 83 forms a load bearing surface 85that contacts the rod portion P1.

As shown in FIG. 2(a) and FIG. 6 , the latch device 1 is fixed to theside frame F11 by bolts 91, 92 and nuts 93, 94. Specifically, the latchdevice 1 is disposed to face the inner side surface of the side frameF11 in the direction of the rotational axis. The bolt 91 extends fromthe inner side of the side frame F11 in the direction of the rotationalaxis, through the interior of the first tubular portion 31 of the firstshaft member 30 and a first hole (not shown) formed in the side frameF11, and is fastened to a nut 93 fixed to the side frame F11. The bolt92 extends from the inner side of the side frame F11 in the direction ofthe rotational axis, through the interior of the second tubular portion51 of the second shaft member 50 and a second hole (not shown) formed inthe side frame F11, and is fastened to a nut 94 fixed to the side frameF11. In this way, the latch device 1 is fixed to the side surface of theside frame F11 facing inward in the direction of the rotational axis.The bolt 91 is an example of a fixing member for fixing the latch device1 to the side surface of the seat frame F1.

As shown in FIG. 6 , the side frame F11 has a frame contact surface F12.The frame contact surface F12 is a surface contactable with the rodportion P1 of the striker P in the locked state, together with the latchcontact surface 22A of the latch 20 and the base contact surface 18 ofthe base member 10. The base contact surface 18 is disposed on the rearside of the rod portion P1 in the locked state which is the same side ofthe rod portion P1 on which the latch contact surface 22A and the basecontact surface 18 are disposed. The frame contact surface F12 isdisposed so as to overlap the base contact surface 18 (the first contactsurface 18A and the second contact surface 18B) as viewed in thedirection of the rotational axis.

A seat belt anchor SA is fixed on the side frame F11. Specifically, theseat belt anchor SA is arranged on a side surface of the side frame F11facing outward in the direction of the rotational axis, with a hole (notshown) formed in the lower end portion thereof being fitted onto a bolt95 fixed to the side frame F11, from the outside of the side frame F11in the direction of the rotational axis, and is fixed to the sidesurface of the side frame F11 facing outward in the direction of therotational axis, by fastening a nut 96 on the bolt 95. A fixing point(bolt 95) of the seat frame F1 and the seat belt anchor SA is located ina position different from a position of the fixing point (bolt 91) ofthe seat frame F1 and the latch device 1 as viewed in the direction ofthe rotational axis. Specifically, the bolt 95 is positioned diagonallyfrontward above of the bolt 91. Further, the bolt 95 is positionedbetween the bolt 91 and the bolt 92 in the front-rear direction.

The operation of the latch device 1 will now be described. In FIGS. 7 to10 , different types of lines are used to illustrate the latch 20, theratchet 40, and the lever member 60 to facilitate understanding.

In the locked state shown in FIG. 3 , the rod portion P1 of the strikerP is located in the access groove 16 of the base member 10, and thelatch 20 is engaged with the rod portion P1 with the hook portion 27holding the rod portion P1 from below. The lock engagement portion 42 ofthe ratchet 40 is located in the lock recess 23 of the latch 20 andrestricts rotation of the latch 20. In the locked state, the tensionspring 70 produces a tensile force, and the lock engagement portion 42abuts the bottom surface of the lock recess 23. Further, in the lockedstate, the rod portion P1 abuts the load bearing surface 85 of the loadbearing member 80.

As shown in FIG. 7 , when the rivet 49 is moved forward from the lockedstate by operating an operating member such as a lever (not shown), theratchet 40 rotates in the counterclockwise direction. This causes theprojection 45 to press the front section of the upper edge of the guidehole 62 of the lever member 60 and rotate the lever member 60 in theclockwise direction while extending the tension spring 70. Althoughthere is not much change in FIG. 7 compared with FIG. 3 , the forceapplied on the lever member 60 from the ratchet 40 tends to graduallyrotate the latch 20 in the counterclockwise direction via the pin 29. Asshown in FIG. 8 , when the rivet 49 is further moved forward, theratchet 40 further rotates in the counterclockwise direction, and thelock engagement portion 42 is disengaged from the lock recess 23. Then,the latch 20 rotates in the counterclockwise direction by the forcereceived from the lever member 60 via the pin 29, and the lockengagement portion 42 faces the open abutment surface 24 of the latch20.

As shown in FIG. 9 , when the operating member is released and the rivet49 moves rearward by the tensile force of the tension spring 70, thelock engagement portion 42 of the ratchet 40 abuts the open abutmentsurface 24 of the latch 20. At this point, the force of the ratchet 40that presses the latch 20 (refer to the arrow) is directed from thecontact point of the lock engagement portion 42 and the open abutmentsurface 24 toward the center of curvature of the open abutment surface24. Since the center of curvature of the open abutment surface 24 isforwardly displaced from the rotational axis A1 across the range withinwhich the open abutment surface 24 abuts the lock engagement portion 42,the force of the ratchet 40 that presses the latch 20 by the biasingforce of the tension spring 70 acts as a force (a rotation moment) torotate the latch 20 in the counterclockwise direction. When thisrotation moment causes the latch 20 to rotate in the counterclockwisedirection, with the open abutment surface 24 sliding along the lockengagement portion 42, as shown in FIG. 10 , the latch 20 becomesdisengaged from the rod portion P1 and unlocked where the rod portion P1is disengageable from the access groove 16 of the base member 10. In theunlocked state, the outer peripheral portion of the latch 20 abuts theconnecting wall 13 of the base member 10, and the latch 20 is not ableto further rotate in the counterclockwise direction. That is, theconnecting wall 13 limits the rotation of the latch 20 in the unlockedstate.

In order to return the latch device 1 from the unlocked state to thelocked state, the rod portion P1 of the striker P is placed in theaccess groove 16 of the base member 10 and pressed against theprojection portion 28 of the latch 20, and the latch 20 is rotated inthe clockwise direction. This causes the latch 20 to engage the rodportion P1. At this point, the lock engagement portion 42 of the ratchet40 that abuts the open abutment surface 24 of the latch 20 slides alongthe open abutment surface 24 and enters the lock recess 23 when itreaches the lock recess 23 by the biasing force of the tension spring70, as shown in FIG. 3 . This causes the latch device 1 to return to thelocked state.

In the locked state, when a load equal to or larger than a predeterminedload is applied to the car seat S to move the car seat S in a frontwarddirection, the car seat S moves in the frontward direction and causesthe latch contact surface 22A of the latch 20 to contact the rod portionP1 of the striker P. If such a load is large, the latch contact surface22A is pressed hardly on the rod portion P1 and a large load is appliedto the latch 20 from the rod portion P1 which rotates the latch 20 inthe counterclockwise direction. In the present embodiment, as shown inFIGS. 11(a), (b), the base contact surface 18 of the base member 10 (thefirst contact surface 18A and the second contact surface 18B) and theframe contact surface F12 of the side frame F11 contact the rod portionP1 together with the latch contact surface 22A. As a result, the loadfrom the rod portion P1 can also be received by the base member 10 andthe side frame F11 in addition to the latch 20.

According to the present embodiment described above, since the basemember 10 is a unitary member including the first support wall 11, thesecond support wall 12 and the connecting wall 13, the number of partsof the latch device 1 can be reduced compared with the case where alatch is disposed between two base members. In a configuration where alatch is disposed between two base members, it is necessary to provide aportion for fixture on each base member to fix the two base members;however, since the base member 10 is a unitary member, such a portionfor fixture will become unnecessary, allowing reduction in the sizeand/or weight of the base member 10. This enables the reduction in sizeand/or weight of the latch device 1 including the base member 10.Further, by the number of parts being reduced, the cost of the latchdevice 1 and/or man-hours for assembly can be reduced.

Since the first shaft member 30 is fixed on the base member 10 andrestricts an increase in distance between the first support wall 11 andthe second support wall 12, the deformation of the base member 10 in thedirection of widening of the distance between the first support wall 11and the second support wall 12 can be minimized. The number of parts ofthe latch device 1 can be further reduced compared with the case wheremembers for restricting the increase in distance between the firstsupport wall 11 and the second support wall 12 are provided aside fromthe first shaft member 30. Since it is possible to reduce the sizeand/or weight of the base member 10 compared with the case where amember for restricting the increase in distance between the firstsupport wall 11 and the second support wall 12 is positioned around thefirst shaft member 30, it is possible to reduce the size and/or theweight of the latch device 1.

Since the latch 20 has a latch contact surface 22A and the base member10 has a base contact surface 18, the rod portion P1 of the striker Palso contacts the base contact surface 18 when it contacts the latchcontact surface 22A. In this way, the load from the rod portion P1 canbe distributed between the latch 20 and the base member 10, and the loadapplied to the latch 20 can be reduced.

Since the base contact surface 18 includes the first contact surface 18Aformed on the first support wall 11 and the second contact surface 18Bformed on the second support wall 12, the load from the rod portion P1can be distributed between the first support wall 11 and the secondsupport wall 12 disposed on both sides of the latch 20. In this way, theload applied to the latch 20 can be further reduced.

Since the first support wall 11, the second support wall 12, and theconnecting wall 13 form a U shape, the base member 10 including thefirst support wall 11, the second support wall 12, and the connectingwall 13 can be easily manufactured by bending a metal sheet, forexample.

Since the first support wall 11 includes a first wall portion 11A, asecond wall portion 11B, and a third wall portion 11C, a stepped shapeis formed on the first support wall 11 and the rigidity of the basemember 10 can thus be enhanced.

Since the first support wall 11 is configured such that the firstconnecting portion 11D and the second connecting portion 11E each have ashape in which two arcuate portions R1, R2 are aligned in the front-reardirection, the rigidity of the base member 10 can be further enhancedcompared with the case where both connecting portions are straight.

Since the lever member 60 is a unitary member including the lever body60A and the spring attachment portion 60B, the number of parts of thelatch device 1 can be reduced compared with the case where a rivet orthe like is attached for engaging the tension spring 70 to the levermember 60.

Since the seat frame F1 has a frame contact surface F12, the rod portionP1 also contacts the frame contact surface F12 when it contacts thelatch contact surface 22A and the base contact surface 18. Whereby, theload from the rod portion P1 can be distributed among the latch 20, thebase member 10, and the seat frame F1, and the load on the latch 20 canbe further reduced.

Since the load bearing member 80 is included, the rod portion P1 abutsthe load bearing surface 85 of the load bearing member 80 made ofplastic and is kept from directly contacting the base member 10, and thenoise produced by contact of the rod portion P1 and the base member 10can be reduced. Further, the peeling of anticorrosive coating or thelike applied on the rod portion P1 or the base member 10 can beminimized.

Since the inner peripheral surface of the first opening 21 of the latch20 is covered with a plastic cover 20B, the sliding resistance betweenthe inner peripheral surface of the first opening 21 and the outerperipheral surface of the first tubular portion 31 of the first shaftmember 30 can be reduced, and a smooth rotation of the latch 20 can beachieved. Further, noise caused by the contact of the latch 20 and thefirst shaft member 30 can be reduced. Since the inner surface of theengagement groove 22 of the latch 20 is covered with a plastic cover20B, noise caused by the contact of the rod portion P1 and the latch 20can be reduced. To achieve the same advantageous effect, the innerperipheral surface of the second opening 41 of the ratchet 40 may becovered with plastic.

Since the reinforcing projection 11P is formed on the first support wall11 of the base member 10, the rigidity of the base member 10 can befurther enhanced. Further, since the ratchet 40 is attached to thehighly rigid reinforcing projection 11P via the second shaft member 50,the ratchet 40 can be firmly attached.

Since the guide recess 17 is formed on the base member 10, the range ofmovement of the rivet 49 can be restricted by the end faces of the guiderecess 17 (restriction projections 17A, 17B). This structure forrestricting the range of movement of the rivet 49 can be easily achievedby a simple structure in which a recess (guide recess 17) is formed onthe base member 10.

Although an embodiment of the present invention has been describedabove, the present invention is not limited to the above-describedembodiment. The specific configuration may be appropriately changed asdescribed below without departing from the gist of the invention.

For example, in the above-described embodiment, the fixing point of theseat frame F1 and the seat belt anchor SA is located in a positiondifferent from that of the bolt 91 as viewed in the direction of therotational axis; however, this is not essential.

As shown in FIG. 12 , a fixing point of the seat frame F1 and the seatbelt anchor SA may be positioned in the same location as that of a bolt97 (the rotational axis A1 of the latch 20) as the fixing member asviewed in the direction of the rotational axis. As one example, thelatch device 1 and the seat belt anchor SA are fixed on the side frameF11 by the bolt 97 and a nut 98. Such a structure can serve to reducethe number of parts of the car seat S since the bolt 95 and the nut 96of the above-described embodiment can be omitted. This enables thereduction of weight of the car seat S and/or the reduction of man-hoursfor assembly of the car seat S. On the other hand, as described in theabove embodiment shown in FIG. 6 , by locating the fixing point of theseat frame F1 and the seat belt anchor SA in a position different fromthat of the bolt 91 (fixing member), it is possible to reduce twistingof the latch 20 which would occur when the seat belt anchor SA ispulled, compared with the case where the latch device 1 and the seatbelt anchor SA are both fixed on the seat frame F1 by the bolt 91.

In the above-described embodiment, the base member 10 is configured suchthat the connecting wall 13 connects the rearward ends of the firstsupport wall 11 and the second support wall 12; however, this is notessential. For example, as shown in FIGS. 13 (a), (b), a base member 110may be configured such that a connecting wall 113 connects the lowerends of a first support wall 111 and a second support wall 112. Thefirst support wall 111, the second support wall 112 and the connectingwall 113 form a near U shape as viewed in the front-rear direction.

In the above-described embodiment, the first connecting portion 11D andthe second connecting portion 11E of the first support wall 11 each havea shape in which two arcuate portions R1, R2 are aligned in thefront-rear direction as viewed in the direction of the rotational axis;however, this is not essential. For example, the first connectingportion and the second connecting portion may each have a shape withonly one arcuate portion or a shape in which three or more arcuateportions are aligned. Further, the first connecting portion and thesecond connecting portion may be straight or have a shape including bothan arcuate portion and a straight portion as viewed in the direction ofthe rotational axis. The first connecting portion and the secondconnecting portion may have a shape different from each other as viewedin the direction of the rotational axis.

In the above-described embodiment, the first support wall 11 isconfigured such that the portion of the first wall portion 11A on whichthe ratchet 40 is attached (reinforcing projection 11P) projectsrelative to the other portions of the first wall portion 11A; however,this is not essential. For example, the first support wall may beconfigured such that the portion on which the latch is attached projectsrelative to the other portions. Further, the first support wall may beconfigured such that it does not have a projecting portion such as thereinforcing projection 11P of the above-described embodiment.

In the above-described embodiment, a stepped shape is formed in thefirst support wall 11 by providing the first support wall 11 with thefirst wall portion 11A, the second wall portion 11B, and the third wallportion 11C; however, this is not essential, and the first support wallmay not have a stepped shape formed thereon, for example. Further, astepped shape may be formed on the second support wall.

In the above-described embodiment, the base contact surface 18 includesthe first contact surface 18A formed on the first support wall 11 andthe second contact surface 18B formed on the second support wall 12;however, this is not essential, and the base contact surface may beformed on only one of the first support wall and the second supportwall. The car seat may be configured such that it does not include abase contact surface, and a latch contact surface and a frame contactsurface are contactable with the rod portion. The car seat may also beconfigured such that it does not include a frame contact surface, and alatch contact surface and a base contact surface are contactable withthe rod portion. The car seat may also be configured not to includeeither a base contact surface or a frame contact surface.

In the above-described embodiment, the first shaft member 30 (shaftmember) by which the latch 20 is rotatably supported restricts theincrease in distance between the first support wall 11 and the secondsupport wall 12; however this is not essential. For example, theincrease in distance between the first support wall 11 and the secondsupport wall 12 may be restricted by a member, other than a shaft membersuch as a rivet, positioned around the shaft member. The increase indistance between the first support wall 11 and the second support wall12 may also be restricted by forming on at least one of the firstsupport wall and the second support wall a portion that bends andextends toward the other support wall, aside from a connecting wall, andwelding or otherwise joining that portion to the other of the firstsupport wall and the second support wall.

In the above-described embodiment, the first shaft member 30 and thesecond shaft member 50 are formed like tubes, and the latch device 1 isfixed on the seat frame F1 by bolts 91, 92 passing through the tubes;however, this is not essential. For example, the latch device may befixed to the seat frame by a bolt passing through a hole formed in thebase member around a shaft member. In this case, the shaft member doesnot have to have a tubular shape. According to the above-describedembodiment, the size and/or weight of the base member 10 can be reducedcompared with the case where a bolt passes through and is fixed aroundthe shaft member, and reduction of size and/or weight of the latchdevice 1 can be achieved. The fixing member is not limited to a bolt andmay be a rivet or the like.

In the above-described embodiment, the lever member 60 is a unitarymember including the lever body 60A and the spring attachment portion60B; however, this is not essential, for example, a rivet or the likemay be attached to a lever member and a tension spring may be engagedwith this rivet. That is, the lever member and the member the tensionspring is engaged with may be different members. In the above-describedembodiment, with regard to the ratchet 40, the tension spring 70 isengaged with the rivet 49 connected to the ratchet 40; however, this isnot essential, and a portion which is engaged with the tension springmay be unitarily formed on the ratchet. Needless to say, the biasingmember is not limited to a coil spring (tension spring 70).

The configuration of each member in the above-described embodiment is anexample, and the members may have different configurations as long asthey have similar functions. For example, as shown in FIG. 14 , a loadbearing member 180 may be configured to include a body portion 181, ahook portion 182, a first load bearing surface 183, an insert portion184, a second load bearing surface 185, and a third load bearing surface186.

The body portion 181 is provided nearly in the shape of a plate andextends approximately in the up-down direction along the first wallportion 11A of the base member 10 toward the third wall portion 11C, asshown in FIG. 15 . The body portion 181 gradually increases in thicknesstoward the upper side thereof, as viewed from the front-rear direction.

The hook portion 182 is a portion that is engaged with the end of thefirst wall portion 11A opposite to the third wall portion 11C. In moredetail, the hook portion 182 is engaged with the deepest portion of theaccess groove 16 formed in the first wall portion 11A (also refer toFIG. 16 ). The hook portion 182 includes an extending portion 182A whichextends from the lower end of the body portion 181 in the direction ofthe rotational axis, and an opposing portion 182B which extends upwardfrom the tip of the extending portion 182A and sandwiches the first wallportion 11A in cooperation with the body portion 181. The upper surfaceof the extending portion 182A is formed in a shape which nearly followsthe shape of the bottom surface of the access groove 16.

The first load bearing surface 183 is the underside surface of the loadbearing member 180 and is contactable with the rod portion P1 of thestriker P located in the access groove 16, in the locked state. Thefirst load bearing surface 183 receives a load from the rod portion P1in a direction from the end portion of the first wall portion 11A (thedeepest portion of the access groove 16) toward the third wall portion11C, specifically, from the underside toward the upper side.

The insert portion 184 is configured to project upwardly from the uppersurface of the body portion 181. In the present modification, the basemember 10 is formed with an insert hole 19A which passes through thethird wall portion 11C in the up-down direction, in place of theengagement hole 19 (see FIG. 2(a)) described in the above embodiment,and the insert portion 184 is engaged with this insert hole 19A. Asshown in FIG. 16 , the insert portion 184 has an insert portion body184A and a pair of front and rear claws 184B. The claws 184B extenddiagonally downward from the upper end of the insert portion body 184Aaway from the insert portion body 184A. The insert portion 184 isconfigured such that the claws 184B elastically bend, and is therebyengageable with the insert hole 19A. The lower ends of the claws 184Bare engaged with portions frontward and rearward of the insert hole 19Aon the upper surface of the third wall portion 11C when the insertportion 184 is engaged with the insert hole 19A, and the claws 184Bthereby sandwich the third wall portion 11C in cooperation with the bodyportion 181.

Returning to FIG. 15 , the second load bearing surface 185 is an uppersurface of the extending portion 182A and is contactable with an end ofthe first wall portion 11A, specifically, the bottom surface of theaccess groove 16. The second load bearing surface 185 contacts thebottom surface of the access groove 16 when the first load bearingsurface 183 receives a load from the rod portion P1 of the striker P.The third load bearing surface 186 is the portion of the upper surfaceof the body portion 181 around the insert portion 184, and iscontactable with the third wall portion 11C. The third load bearingsurface 186 contacts the third wall portion 11C when the first loadbearing surface 183 receives a load from the rod portion P1 of thestriker P.

According to such a load bearing member 180, since the insert portion184 is engaged in the insert hole 19A of the third wall portion 11C, itis possible to restrain the load bearing member 180 from moving in thedirection of the rotational axis (particularly to restrain the bodyportion 181 from moving in a direction away from the first wall portion11A) when the first load bearing surface 183 receives a load from therod portion P1 of the striker P. In this way, the load imposed from therod portion P1 can be stably received by the metal base member 10 viathe load bearing member 180.

By providing the load bearing member 180 with a second load bearingsurface 185, the load imposed on the load bearing member 180 from therod portion P1 can be stably received by the first wall portion 11A(base member 10) via the second load bearing surface 185.

By providing the load bearing member 180 with a third load bearingsurface 186, the load imposed on the load bearing member 180 from therod portion P1 can be stably received by the third wall portion 11C(base member 10) via the third load bearing surface 186.

By providing the insert portion 184 with claws 184B which sandwich thethird wall portion 11C in cooperation with the body portion 181, it ispossible to restrain the load bearing member 180 from moving in theup-down direction (in the direction of thickness of the third wallportion 11C).

In the above-described embodiment, the latch device 1 is attached to theleft side frame F11 of the seat frame F1; however this is not essential,for example, the latch device may be attached to the right side frame.The latch device may also be respectively attached to the right and leftside frames. Further, only one latch device may be attached at or nearthe center of the frame of the seat cushion in the left-right direction

In the above-described embodiment, the seat frame F1 is a frame of theseat cushion S1; however, this is not essential, for example, the seatframe may be a frame of a seat back. In other words, the latch devicemay be attached to and used with a frame of a seat back. The latchdevice may also be used as a device for locking a part of a car trunk orthe like which opens and closes.

In the above-described embodiment, a car seat S installed on anautomobile is given as an example of a vehicle seat; however, this isnot essential, and the vehicle seat may be a seat installed on a vehicleother than an automobile, for example, a train, a ship, or an airplaneor the like.

Each of the components described in the above embodiments andmodifications may be implemented appropriately in combination.

The invention claimed is:
 1. A latch device, comprising: a latch, thelatch device being capable of transition to a locked state in which thelatch is engaged with a rod portion and transition to an unlocked statein which the latch is disengaged from the rod portion, a shaft memberthat supports the latch in a manner that permits the latch to rotate;and a base member that supports the shaft member, the base memberincluding an access groove in which the rod portion is located in thelocked state; and a load bearing member disposed on a bottom of theaccess groove, the load bearing member having a U-shaped cross sectionconfigured to sandwich the base member, wherein, in the locked state,the load bearing member is configured to receive a load applied from therod portion to the base member, wherein the base member furthercomprises: a first support wall disposed on one side of the latch in adirection of a rotational axis of the latch and configured to supportone end of the shaft member, the first support wall having an engagementhole formed therein, wherein the first support wall includes a wallportion defining a plane extending in the direction of the rotationalaxis, the engagement hole being formed in the wall portion, and whereinthe load bearing member comprises: a first clamping portion, and asecond clamping portion spaced apart from the first clamping portion inthe direction of the rotational axis; and a connecting portion thatconnects lower sections of the first clamping portion and the secondclamping portion, wherein the load bearing member includes an engagementlug formed on an end portion of the load bearing member, the engagementlug being configured to engage the engagement hole, wherein theengagement lug is formed on the second clamping portion, and the loadbearing member is fixed to the base member by the first clampingportion, the second clamping portion, the engagement hole, and theengagement lug.
 2. The latch device according to claim 1, wherein theconnecting portion has an underside surface that forms a load bearingsurface configured to contact the rod portion in the locked state. 3.The latch device according to claim 1, wherein the engagement lug isconfigured to protrude upwardly from an upper surface of the secondclamping portion.
 4. A latch device, comprising: a latch, the latchdevice being capable of transition to a locked state in which the latchis engaged with a rod portion and transition to an unlocked state inwhich the latch is disengaged from the rod portion, a shaft member thatsupports the latch in a manner that permits the latch to rotate; and abase member that supports the shaft member, the base member including anaccess groove in which the rod portion is located in the locked state;and a load bearing member disposed on a bottom of the access groove, theload bearing member having a U-shaped cross section configured tosandwich the base member, wherein, in the locked state, the load bearingmember is configured to receive a load applied from the rod portion tothe base member, wherein the base member further comprises: a firstsupport wall disposed on one side of the latch in a direction of arotational axis of the latch and configured to support one end of theshaft member, the first support wall having an engagement hole formedtherein, and wherein the load bearing member comprises: a first clampingportion, and a second clamping portion spaced apart from the firstclamping portion in the direction of the rotational axis; and aconnecting portion that connects lower sections of the first clampingportion and the second clamping portion, wherein the load bearing memberincludes an engagement lug formed on an end portion of the load bearingmember, the engagement lug being configured to engage the engagementhole, wherein the engagement lug is formed on the second clampingportion wherein the engagement lug is configured to protrude upwardlyfrom an upper surface of the second clamping portion, and the loadbearing member is fixed to the base member by the first clampingportion, the second clamping portion, the engagement hole, and theengagement lug.
 5. The latch device according to claim 4, wherein theconnecting portion has an underside surface that forms a load bearingsurface configured to contact the rod portion in the locked state. 6.The latch device according to claim 4, wherein the first support wallincludes a wall portion extending in the direction of the rotationalaxis, the engagement hole being formed in the wall portion.